Problem: If $a + b = -1$ and $x + y = -10$, what is $2b - 6x - 6y + 2a$ ?
Solution: $= 2a + 2b - 6x - 6y$ $= (2) \cdot (a + b) + (-6) \cdot (x + y)$ $= (2) \cdot (-1) + (-6) \cdot (-10)$ $= -2 + 60$ $= 58$